I'm awful on weekends! Since starting WW, I've tried to be "extra" good during the week at stay at my daily points which allows for some wiggle room on the weekend. I do tend to graze a bit more but I try to make it good stuff.
When my husband polished off a pint of ice cream, I didn't want to sulk and go without anything so I got a little plain nonfat yogurt and mixed some sugar free chocolate pudding in. I was at my points for the day but it wasn't nearly as bad as ripping the carton out of his hand and chowing down.
I find the weekly points get me through the weekend sane and content.
Full disclosure: I only eat about 1/2 of my weeklies and still find I'm losing at a nice rate. I just fear I underestimate on some foods that can't be easily weighed and measured so I like to give myself a healthy cushion (pun intended).